Airplane having variable lifting surfaces



July 28, 1936. J. GERIN AIRPLANE HAVING V.ARIABLE LIFTING SURFACES 6Sheets-Sheet l Filed April 4, 1935 N N a Mos.

y 1936- J. GERIN AIRPLANE HAVING VARIABLE LIFTING SURFACES.

Filed April 4, 1955 6 Sheets-Sheet 2 .FiGQ.

July 28, 1936.

J. GERIN AIRPLANE HAVING VARIABLE LIFTING SURFACES Filed April 4, 1955 6Sheets-Sheet 3 July 28, 1936. J. GERIN AIRPLANE HAVING VARIABLE LIFTINGSURFACES 6 Sheets-Sheet 4 Filed April 4,1935

lllll l July 28, 1936. J, GERfN 2,049,006

, AIRPLANE HAVING VARIABLE LIFTING SURFACES Filed April 4, 1935 6Sheets-Sheet 5 July 28, 1936. J. GERIN 2,049,006

AIRPLANE HAVING VARIABLE LIFTING SURFACES Filed pril 4, 1935 eSheets-Sheetfi 115 L 15? 1 114 115 f 127 112 L L l Li.

I 12s 10 1 111 I 109 108 10o fl 15a wag} 129 J 10 f gi /36w PatentedJuly 28, 1936 AIRPLANE HAVING VARIABLE LIFTING SURFACES Jacques Gerin,Boulogne-sur-Seine, France Application April 4, 1935, Serial No. 14,681In France April 7, 1934 6 Claims.

Airplanes having a variable lifting surface are already known,particularly by the United States Patents No. 1,787,517, dated 6thJanuary 1931 and No. 1,979,194, dated 30th October 1934, in the name ofthe applicant, in which some of the fixed planes and, more especially,the lift- 'ing wings, devised for flight at a high speed, aretransformed, for flight at low speed and for flying off or landing, intoplanes of the same span A but of much greater depth, owing to flexiblemovable surfaces wound on drums or extended along fixed planes. The freeend of each flexible surface is urged, in the direction for extension orunwinding, by a cable, or its equivalent, which passes to the end of thecorresponding fixed lifting surface in order to wind up on a drivingdrum.

The present invention relates to improvements in airplanes of the typepreviously defined and is mainly characterized by the following points,applied separately or according to any combinations:

(a) A drum for winding up a cable for pulling out the flexible surfaceand a drum for winding up or retracting this flexible surface, aredriven, from one and the same motor, rotating in both directions,through the medium of movement selecting devices, such as free wheels,with suitable speed reducing ratio, so that for pulling out the flexiblesurface, the free wheel driving the drum of this flexible surface shouldbe actuated in its free direction with a certain lead, the free wheeldriving the drum of the cable being actuated in the driving direction;for retracting the flexible surface, the free wheels are driven indirections reverse to those indicated.

(2)) The motor is always directly connected to the free wheel of thedrum for winding up the cable, the speed of rotation of this free wheelhaving a constant ratio relatively to that of the motor. 7

' (c) The free wheel driving the drum for winding up the flexiblesurface is driven, in the winding up direction, by a first speedreducing device .and at a lower speed than for the unwinding operationwhich is effected through the medium of a second speed reducing device,an automatic rocker ensuring. the setting in action of the first -orsecond speed reducing device, according to the direction of displacementof the flexible surface.

.i(d) Friction devices are combined with the .drums.

(e) The rocker is mounted on the shaft of the motor oron a shaftdirectly driven by the latter,

through the medium of a friction device ensuring its temporary angularconnection with said shaft, which rocker, in position of rest, does notallow any connection with the motor and the .two speed reducing devicescontrolling the drum of the flexible surface.

(1') The closing of the circuit of the motor, for ensuring itsdisplacement in one direction or the other, causes an angulardisplacement of the rocker in the same direction in order that it shouldcome in engagement with a corresponding wedge-shaped contact ensuring,on the one hand, disengagement between the rocker and the motor and, onthe other hand, the closing of themain circuit, this allowing to releasethe hand oper- 15 atedicontac't knob," as well as the closing of one ofthe electromagnets holding said rocker in the position of engagement ofone of the speed reducing devices of the drum of the flexible surfacewith the motor.

(g) The end of the displacement of the flexible surfaces ensures theopening of the circuit of the motor and the opening of the circuit ofthe electromagnet holding the rocker which then returns to itsintermediate position under the action of a resilient returning device.

(h) An end box or casing for each movable flexible surface is of rigidconstruction and it is perfectly guided on the corresponding fixed wingfor constituting, on the one hand, a resistant element on which theflexible surface engages and, on the other hand, a stream-linedconnection between the fixed Wing and the fuselage, during retraction ofthe flexible surface.

(1) For limiting oblique stresses on the flexible surface, particularlyduring unwinding of the latter, use is made of a light carriage rollingon the front portion of the fixed wing so as to absorb these obliquestresses, said carriage being preferably combined with the rigid end boxor casing.

(7') The movable flexible surface which, when wound up, is retractedwithin the fuselage for instance, determines at the beginning of itsunwinding movement and in antagonism to the action of returning means,the opening of a shutter normally closing an opening provided for thepassage of the flexible surface, this shutter constituting a guide forthe latter.

(k) The returning means, constituted for instance by an elastic cablefor each flexible sur- 5O face, act, at the end of the movement of thelatter and particularly on the corresponding rigid end box or casing,for completing the retraction of the flexible surface in case one of themovable flexible surfaces is completely wound up before the othercorresponding movable flexible surface, the circuit of the driving motorhaving been opened by the first retracting operation.

(1) Each movable shutter, normally held in closed position by thereturning means, is connected to a cable which, in retracted position,is rigid with one of the elements of the corresponding flexible surfaceand particularly with its movable end box or casing; this cable moves inthis box or casing at the beginning of the unwinding operation foropening the shutter in antagonism to the action of the returning sandowand it engages, after a movement of small ampli tude, with a fixed partby disengaging from the movable flexible surface.

(m) The engagement of the cable with the movable flexible surface orwith the fixed point is automatically ensured by the displacement ofthis flexible surface which acts, for that purpose, on a rocker engagingwith the said cable for releasing the flexible surface or reversely. Y

(n) The control of the various drums from the motor is ensured bynonreversible devices, particularly of the worm and worm wheel type, forconstituting a safety device.

(o) The motor for one and the same group of flexible surfaces canrotatein both directions, its

current sup-ply being controlled by the energization of either of twoelectromagnets which operate contacts for the flow of current in onedirection or the other.

(p) A so-called retracting knob and another so-called spreading out knobensure the energization of either of the electromagnets operating thecontacts energizing the motor, the beam driven by the motor ensuring theclosing of the contact which, in its turn, ensures the permanent closingof the circuit energizing the electromagnet put in action, when the knobpreviously actuated is released, the circuit being broken when theflexible surfaces act on so-called extreme retracting or extremespreading out contacts, according to circumstances.

(q) When the flexible surfaces are being wound up or unwound, the actionon the spreading out knob or on the retracting knob first causes thepre-established circuit to be broken .and to stop the motor, .then toclose a supply :circuit for imparting to the flexiblesurface adisplacement reverse to that to which theywere subjected.

The invention further relates to other features which will appear fromthe following description with reference to the accompanying drawings,given by way of exampleonly, and in which:

Fig. 1 is a diagrammatic perspective viewof aform of construction ofthedevice for controlling the movable flexible surface.

Fig. 2 is a side view of a practical embodiment of the devicediagrammatically illustrated in the preceding figure.

- Fig. 3 is a corresponding elevation.

Fig. 4 is a partial plan view of the movable flexible surface inextended position on the fixed wing.

Fig. 5 is a partial view, on an enlarged scale of the endof the flexiblesurface or movable box Fig. 9 is a diagrammatic view of a control deviceof the electric motor actuating a group of flexible surfaces.

Fig. 10 is a front view of a board associated with this control device.6 The control for the movable flexible surface is diagrammaticallyillustrated in Fig. 1 in order that it should be more clearlyunderstood, this figure showing only an explanatory diagram of a form ofconstruction, a practical embodiment of 10 which is illustrated in Figs.2 and 3.

This control device comprises a main motor I, which can rotate in bothdirections according to the manipulation of the control members whichwill be subsequently described with the electric 16 diagram ofconnections of the installations on board an airplane. This motoractuates a drum 2 on which winds a cable 3 passing for instance on apulley 4 arranged at the end of one of the fixed lifting surfaces of theairplane. This cable 3 is 20 attached, at 5, to the. end of the movablelifting .surface 6 (diagrammatically illustrated), Which'is wound up, inretracted position, on a drum '1. y The drum 2 is driven by the motor Ithrough the medium, of a worm 8 fast on the shaft 9 of the 26 motor andmeshing with a worm wheel 10 rigidly secured on a shaft H carryinganother worm I2 meshing with a worm wheel I 4. The latter drives theshaftv l5, rigid with the drum 2. under the control of a movementselecting device l6 con- 8 stituted by a free wheel. 7

On the other end of. theshaft 9 of the motor .I is.rigidly secured atoothed wheel l7, which can mesh, through the medium of a rockerillustrated only in Figs.2 and 3, either with a toothed wheel ll [8, orwith a toothed wheel IS. The toothed wheel I 8 is directly and rigidlysecured on a shaft 20 carrying a worm 2| meshing with a worm wheel 22.The later drives the shaft 2.3, carry- .ing the drum 1, only in onedirection owing to a in movement selecting device 24 constituted by afree wheel. The gear l9 drives the shaft .20 l

throughthe medium of the shaft 25 and ofgears 28, 21 and 28.

The worm and worm wheel mechanism constivt-utes a safety device.

The free wheel l6 loosely rotates in the direction of the arrow 30anddrives the shaft [Stanly in the direction of the arrow 29. Likewise, thefree wheel 24 loosely rotates in the direction of 0 the arrow 3! anddrives the shaft23 inthe direction of the arrow 32. Moreover, frictiondevices arecombined with the drums, as will be described with, referenceto Figs. 2' and .3.'.

The directions of rotation of the various members, for unwinding theflexible surface, are indicated by uncrossed arrows, and the directionsof rotation of these members, for winding upor retracting the flexiblesurface, are indicated by crossed arrows. 59

For unwinding the flexible surface, the motor I .rotates in thedirection of the arrow and the drum 2 in the direction of thearrow .29.In this case,1the toothed wheel I! meshes-with the toothed wheel l8 andthe free wheel 24 is driven, as

ing down between the shaft 9 and the toothed wheel 22, when the gear I8is used, is chosen with :a ratio of. 256. The gearing down between theshaft 9 andthe toothed wheel 22, when the gear I 18 is used, is chosenwith a ratio of 768. This variation of gearing down ratio is necessaryin order that the vnnding up of the flexible surface :on the drum 1should be correctly effected, the latter being then driven by the motorwhich, in

10 this case, rotates in the direction of the arrow 40, by utilizing thegear 19. In fact, it is necessary that the speed of the drum 2, when thecable 3 unwinds and is driven by the sail winding up on the drum 1,should remain lower than -.the speed of the wheel l4. This importantdifference in the ratios is due to the fact that the maximum diameterwhen the flexible surface is wound up is much larger than the winding updiameter of the drum 2 which remains constant.

A brake, acting on the drum of the cable, allows of slightly stretchingthis cable between the drum and the flexible surface.

In the practical embodiment illustrated in Figs. 2 and 3, the motor isindicated at I, the drum for winding up the cable at 2, and the shaft oftwo drums on which two movable flexible surfaces wind up, are indicatedat 23. The other parts are also indicated by the same reference numbersas in Fig. 1, but the gear I1 no longer acts directly on the gear l8 oron the gear I9, the transmission being ensured in this case .through themedium of the gear Il the latter :meshing, either with the gear I9, orwith the gear l8. The transmission between the gears 1.8 or l9 and theshaft 23 is ensured through the medium of various gears. Brakes 50, 5|and 52 are provided for exerting a braking action on the drums 2 and 1.

According to a particularly important feature of the present invention,a rocker 53, provided with two side cheek members 53* pivoted at 54,

is mounted on the shaft 9 of the motor. The angular connection betweenthe rocker 53 and theshaft 9 is ensured by friction discs 55 which areput out of action as soon as the cheek members 53 are moved away fromeach other. The .rocker 53 is held in mean position, in which the gearI'I does not mesh with the toothed wheels l8 and I9, through the mediumof at least one v resiliently 'distortable blade 51 rigid, at one ofitsends at 58, with the rocker 53 and extending between two fixedabutments 59,=which latter are preferably provided with rollers.

v The closing of the circuit of the motor ensures the rotation, in thedesired direction, of the shaft .9 .of the motor I; this shaft 9 drives,in the same direction, .the rocker 53 which engages either with .a-wedge6|, or with a wedge 62 which is thereby inserted between the cheekmembers 53 restored to closing position by springs 63. The cheek members.or jaws 53 are thus slightly moved apart so as to put out of action thefriction clutch 55 and thereby release the rocker from the motor shaft9.

The wedges 6] and 62 are so devised as to constitute contacts, in such amanner that by engagement of the rocker 53 with one of these contacts 6|or 6.2, the circuit of one of the electromagnets 6i or 62 is closed,without having to manually maintain the initial contact of the maincircuit. The energized electromagnet holds the rocker 53 in position forsecurely holding the gear l'l in engagement with one of the gears l8-:or l: 9 according as the flexible surface is extended 5 .or retracted,At each end of the displacement of the flexible surface, in onedirection or the other, this flexible surface acts on switches openingthe circuit of the motor and that of the locking electromagnet, so as toallow the rocker to :return to its mean position under the action of 5its spring 51, whilst ensuring theengagement'of the friction clutch 55allowing to render the rocker 53 rigid with the motor shaft 9. Thevarious control members have thus been restored to their initialposition for allowing, in the same condi- 10 tions as those previouslyindicated, a further displacement of the movable flexible surface.

The two cables 3, which exert a pull on the flexible surfaces and windup on the drum 2, are guided by any suitable means, and particularly 15by a screw and nut device 65 for causing the cables to helically wind upon the drum.

It will be noted, according to an important feature of the presentinvention, the box or casing 66, constituting the end of a movable wing,20

is rigid and perfectly guided on the fixed portion 61. of the wing. Themovable flexible wing is secured to the rigid box or casing which exertsa pull on this flexible wing duringunwinding and allows this flexiblesurface to be extended 25 out during flight at high speed. The movablebox or casing 66 always remains on the fixed portion 61, even when theairplane is taken to pieces for shipment. In this case, the wing whichis connected by false ribs to the box or casing, is dis- 30 engaged fromthe latter by removing the screws 66 and 66 In this way, the adjustmentof the pulling cables is not disturbed.

' For avoiding side pulls on the flexible surface when the latter isbeing unwound and any wedg- 35 ing of the movable box or casing 66 (Fig.3)

on the fixed portion 61 of the wing, the movable box or casing isprovided with a carriage 68 guided on the leading edge 69 of the fixedwing.

This carriage is provided with wheels 10 and 'il 40 so as to exert,through cables 12 and '13, a pull on the ribs absorbing the obliquestresses. Such a device is more particularly illustrated in Figs.

4, 5 and 6.

Figs. 7 and 8 diagrammatically illustrate a form of construction of adevice for actuating a shutter 15 pivoted at 16 on the fuselage 11 ofthe airplane, and which, in closed position, constitutes a portion ofthe covering of this fuselage. This shutter 15, illustrated in. fulllines in its 50 open position, and in dot and dash lines in its closedposition, controls an opening I8 through which the movable flexiblesurface can move, this shutter also constituting a slide or a guideincline for the displacement of this flexible surface.

The shutter 15 is provided with an arm 19 to the end of which arepivoted, through the medium of a member mounted, by means of a rubberblock, on a pivot pin 8| of the arm 79, on 69 the one-hand, an elasticmember 8| connected to a fixed point 82 and, on the other hand, a cable83 passing on guide pulleys 8E- and 85 and terminating in an eye 86. Thelatter can engage either with a hook 81 rigid with the mov- 5 vableflexible'surface and secured to the movable box or casing 66, or with arocker 88 pivoted about va fixed point 89.

The operation of this device is as follows:

The eye 86 being initially engaged with the 79 hook 81 rigid with themovable flexible surface, the displacement of the latter in thedirection for unwinding (arrow 96) causes the actuation of the cable 83which causes the shutter 15 to pivot in the direction of the arrow 9|for'opening said --in a notch 94 of the rocker shutter andtherebyincreasing the tension of the elastic member 8|, which isinitially stretched to a certain degree for holding the shutter inclosed position.

After. a slight initial unwinding movement of the movable flexiblesurface, the hook 81, or an abutment adjacentto the latter, acts on thearm .92 of the rocker88 which is movedin the direction of the arrow 93,actuating the eye 86 which is released from the hook 8! and heldstationary 88. The movable flexible surface continues its movement, theshutgized.

:ter 15 being held open and the eye 86 being held stationary by therocker.

At the end of the retracting movement of the movable flexible surface,the hook 81, or an abutment adjacent to the latter, acts on the arm ofthe rocker 38 for angularly moving the latter in the direction of thearrow 9t. This movement releases'the eye 86 which engages with the hook81 and moves with the flexible surface in the direction of the arrow 97for a relatively short distance of the end of the retracting movement,this allowing, under the action of the elastic member 8I,'to close theshutterlE.

Independently of the function previously indicated, the deviceillustrated in Figs. '7 and 8, fulfills another 'very important functionwhen both movable flexible surfaces of one and-the same wing do notreach the retracted position rigorously at the same time. The flexiblewing retracted with a certain lead owing to the variations in thewinding up on its corresponding drum,

opens the circuit of the driving motorand the lagging flexible wing isthen automatically moved to the end abutment by the correspondingelastic member. The unavoidable variations occuring in the winding up'operation are thus automatically compensated. Moreover, the end box orcasing 66 tained by reversal of the current in the armature.

I02 and I03 designate movable contacts normally restored by springs tothe position they occupy in the drawings and which can be respectivelymoved in contact with fixed keys I04 and I05 when the electromagnets Hi6and I 07 areener- I08 and I09 designate electromagnets the energizationof which holds the beam in position for closing contacts H0 and III. H2and H3 designate extreme spreading out switches for the flexiblesurfaces. They are closed when the flexible surfaces are retracted andopen when they reach the end of their extension movement.

- I I4 and I I5 designate the extreme retracting switches. They areclosed when the flexible surfaces are extended and are automaticallyopened when they reach the end of their retracting'movement. H6 and II!designate double contact switches operated by the pilot. The switch II 6is designated by the expression spreading'out knob and the switch II! bythe expression retracting knob. Normally, when these knobs are notactedupon, the contacts are closed at I I8 and 1H9 and open at I20 and l2I IBy-a single operastored to the mean "I'hesource'of current supplyfeeding the installation is shown as being constituted by'a battery I23;

\ The.operation of the installation :is as follows: The switch I 22being closed and all the contacts being in the position shown in thediagram, the

drums." r

For spreading them out, the pilot presses upon the spreading out knobH6. The contact I I8 is opened and the contact I 20-is closed. Acircuitflexible surfaces are retracted and wound ontheir 'is closed frompositive pole of the battery I23,

throughswitch I22, contact II9,wire I24, contact I20, wire I25, wireI26, switch II2, wire I21, switch II 3,'wire I28, electromagnet I 01tonegative pole ofthe battery. I

The electromagnet I07 being energized, it closes the contacts atI03--I05'. -A second circuit is closed from positive pole of thebattery, through right-hand. contact -I03-I05, wire I29, armature 500 ofthe motor, wire I30, lefthand contacts I 03- 05, to negative pole of thebatter yi- 'Themotor starts in the direction of the arrow I3I,actuating, as explained above, 'the beam 53 which closes the contactIIO, the latter short-circuiting the contact at I 20. The pilot cantherefore release the knob I I6 which closes the contact at I i 3 andopens it at -I 20, the'motorcontinues torctate and the flexible-surfacesspread out along their fixed planes, On the other hand, the positivepole ofthe battery beingconnectedto the wire I28 as just stated,theelectromagnet I08 is energized through-the wire I-32,'the latter beingconstantly connected to the negative pole'of the battery. Theenergization of the electromagnet I08 holds the beamin position forclosingthe contact I I0, notwithstanding the action of the resilientmeans tending to restore it to'the mean position it occupies in thediagram; 1

If itis assumed that the pilot, for any reason whatever, desires to stopand wind up again the I flexiblesurface's in-course of extensiomhepresses upon the retracting knob III-for opening the contact at- I I9and closing it at I2I. The opening of 'thecontact I I 9 opens thecircuit previously closed through the switch I22, wire I24,contact Theelectromagnet I 01 is no longer energized; the contacts are opened atI03I05 and the motor is stopped. On the other hand,

owing to the fact that the contact is opened at I I9, the wire I28 is nolonger connected to the positive pole of'the battery and theelectromagnet I08 is no longer energized; the beam 53 is reposition itoccupies in the diagram.

The same effects would be produced if the flexible surfaces were spreadout to the maximum extent as, at-the end of their movement, they act onthe contacts I I2 and I I3 for opening them.

But, whether the knob I I1 is acted upon when the flexible surfaces arein course of extension or whenthey are completely spread out, the'following effects occur:

The-contact being closed at I2 I 'and opened at -II9,-"a' circuit isclosed through: positive pole of the battery I23, switch I22, contactI-I8,-wire I33,

contact I2I,wire I34, contacts '5 and H4, wire I35, electromagnetI00,'and negative pole of the battery. 123;: 7 V

---- I'he ""electromagnet 106 being energized, it closes the contacts atI 02--I 04. -Themotor starts in the direction of the arrow I36 and thebeam 53 closes the contact III, the latter short-circuiting the contactI2l the opening of which, when the knob H1 is released, no longerintervenes in the operation in progress. The electromagnet I09 isenergized and holds the beam 53 in position for closing the contact Ill.

It will be seen that the flexible surfaces move in until the spreadingout knob H6 is pressed upon, or, when they reach the end of theirmovement, they act on the switches H4 and H5 for opening them.

For facilitating the operations, a board is arranged in the pilotscockpit, within reach of the pilot. The board shown in Fig. correspondsto a biplane provided with two distinct motors for independent controlof the flexible surfaces of the upper planes and of the flexiblesurfaces of the lower planes.

On this board, H6 and II! respectively designate the retracting andspreading out knobs shown in the diagram of Fig. 9, for the upperplanes. H60. and Illa designate the corresponding knobs for the lowerplanes. I31 and I38 designate ammeters. At I39 is provided an indicatorshowing the charge of the batteries. At 140 and Mlla are arranged theknobs of the master switches for the upper and lower planes. Supervisionmeans are moreover provided and are constituted by lamps of difi'erentcolours.

What I claim as my invention and desire to secure by Letters Patent is:

1. In an airplane, fixed planes, winding drums, flexible planes wound onsaid winding drums, a reversible motor, a cable connected with the freeand of each flexible plane, a winding drum for said cables, meansconnecting the drums of the flexible planes, gearings connecting saidmotor with the first and second mentioned drums for actuating said drumsand extending and retracting the flexible planes, said gearingsincluding free running elements, said motor being adapted, duringoperation, to selectively actuate said drums and extend or retract saidflexible planes in dependence on the direction of movement of saidmotor, and means for interrupting operation of said motor when saidflexible planes reach the end of their extension and retractionmovements.

2. In an airplane, fixed planes, winding drums, flexible planes wound onsaid winding drums, a reversible motor, a cable connected with the freeend of each flexible plane, a winding drum for said cables, meansconnecting the drums of the flexible planes, a gearing connecting themotor with the drum for the cable, said motor including a motor shaft, arocker mounted coaxially with the motor shaft, a pinion on the motorshaft, and a second pinion journalled on the rocker and permanentlymeshing with the first mentioned pinion, separate gear trains bothoperatively connected with the drums of the flexible planes, the secondmentioned pinion being adapted to be brought into operative relationwith one or the other of said gear trains during rocking movement of therocker, a circuit including said motor, means actuated by said rocker toclose said circuit, and means independent of the first mentionedcircuit, closing means for interrupting operation of said motor whensaid flexible planes reach the end of their extension and retractionmovements.

3. In an airplane, fixed planes, winding drums, flexible planes wound onsaid winding drums, a reversible motor, a cable connected with the freeend of each flexible plane, a winding drum for said cables, meansconnecting the drums of the flexible planes, a gear train connecting themotor with the drum for the cable, said motor including a motor shaft, arocker mounted coaxially of said shaft, separate gear trains bothconnected with the cable of the flexible planes, permanently meshingpinions mounted on the motor shaft and rocker, the rocker carried pinionbeing alternately engageable with the respective last mentioned geartrains, means normally tending to move the rocker to an intermediateposition, clutch elements normally establishing a driving connectionbetween the motor shaft and said rocker whereby the latter is coupledwith and oscillated by said motor shaft, means engageable by the rockerto release said clutch elements and permit the motor shaft to revolveindependently of the rocker, an electric circuit including said motor,means controlled by said rocker for closing said circuit and maintainingthe latter closed during the extension and retraction movements of theflexible planes, and means for interrupting operation of said motor whensaid flexible planes reach the end of their extension or retractionmovements.

4. An arrangement as claimed in claim 3 characterized by the provisionof electro-magnetic means interposed in said circuit and arranged atopposite sides of said rocker and coacting therewith to retain saidrocker in adjusted position during the extension and retraction movementof the flexible planes.

5. An arrangement as claimed in claim 1 characterized in that saidflexible planes include ribs and a rigid casing at the end of eachflexible plane, guide pulleys arranged in each casing and movable alongthe leading edge of the fixed planes, a movable bearing for at least oneof said guide pulleys, and a tension cable for connecting the movablebearing to the ribs of each flexible plane.

6. An arrangement as claimed in claim 1, characterized in that saidflexible planes include ribs and a rigid casing at the end of eachflexible plane, guide pulleys arranged in each casing and movable alongthe lea-ding edge of the fixed planes, a movable bearing for at leastone of said guide pulleys, and a tension cable for connecting themovable bearing to the ribs of each flexible plane, said drums beingmounted on the fuselage of the airplane and the latter being providedwith openings for the passage of said casings and flexible planes, ashutter normally closing each opening, and a tension cable normallytending to close each shutter, a second cable connected with eachshutter for moving the latter to open position, an eye at the end of thesecond cable, a hook pivoted to each fixed plane and engageable by saideye for retaining the shutter in open position, and a hook carried byeach rigid casing adapted to disengage said eye from said pivoted hookwhen the flexible plane is retracted.

JACQUES GERIN.

